1. Field of the Invention
This invention relates, generally, to surgical devices, and more particularly relates to devices having utility in the field of heart operations of any type where the operation requires that the functions of the heart be performed by a machine to which the patient is connected during surgery.
2. Description of the Prior Art
A search of United States patents located the following patents:
______________________________________ Patentee U.S. Pat. No. Date of Issue ______________________________________ Hill et. al. 3,776,237 12-04-73 Goosen 4,018,228 04-19-77 Peyman 4,099,529 07-11-78 Downie et. al. 4,216,776 08-12-80 Lary 4,273,128 06-16-81 ______________________________________
The field of search covered Class/Subclass 128/246,305,305.2, and 305.3.
The surgical instruments that are disclosed in the above-listed patents are used to form perforations in the aorta to facilitate subsequent introduction of a cannula, after a slit has been made in the aorta in the conventional manner-with a scalpel. Such devices thus have little relevance in the field of this invention.
No surgical instruments are known that eliminate the use of the scalpel when making a slit in the aorta to allow insertion of a cannula into such aorta. Nor are any instruments known that guide the actual insertion of the cannula after the slit has been made.
A properly designed instrument would lower the level of skill required to perform the cannula insertion, thereby reducing the risk of the procedure. Such an instrument would produce slits that would be precisely the width required for the insertion. Slits of greater width than that required allow bleeding around the perimeter of the inserted tube, and slits of smaller width than required often result in tears in the aorta as the cannula is forced through a too small opening.
There is clearly a need for a surgical instrument that is easy to use, that produces an optimal-size slit in the aorta and that introduces the cannula in a uniform manner, but the required instrument is not found in the prior art.